national aeronautics and space administration · 2013-02-02 · material would weigh a billion tons...

w w w. n a s a . g o v

National Aeronautics and Space Administration

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N av i g ating by Cosmic Beacons

NICER Offers More Bang for the Buck

NASA Lets the ‘ C ATS’ Out of the Bag

First-Ever Unibody Composite Telescope Developed

The Attack of Atomic Oxygen

U p , U p , and Away with NASA’s Satellite on a String

Volume 7 Issue 3 Spring 2011

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h t t p : / / g s f c t e c h n o l o g y. g s f c . n a s a . g o v Volume 7 Issue 3 Spring 2011

Imagine a technology that would allowspace travelers to transmit gigabytes ofdata per second over interplanetary dis-tances or to navigate to Mars andbeyond using powerful beams of lightemanating from rotating neutron stars.

The concept isn’t farfetched.

In fact, Goddard astrophysicists Ke i t hGendreau and Zaven Arzoumanian planto fly a multi-purpose instrument on theI n t e rnational Space Station to demon-strate the viability of two groundbreak-ing navigation and communication tech-nologies and, from the same platform ,gather scientific data revealing thephysics of dense matter in neutron stars(see related story, page 3).

Selected for development by NASA’ sOffice of the Chief Technologist, the X-ray Navigation Demonstrator (XNAV )will include 56 X-ray telescopes, silicon detectors, and anumber of other advanced technologies in a packageabout the size of a large recycling bin. Gendreau and histeam say they plan to deliver the payload to the orbitingoutpost in 2015 to begin the disparate, yet related, inves-tigations.

“It’s rare that you get an opportunity to develop a cross-cutting experiment,” Gendreau said. “This technologytouches seemingly disjointed things: X-ray astrophysics,navigation, and new techniques to communicate overi n t e r p l a n e t a ry distances. The time is right for this experi-ment. This is one that we can do now. ”

Stellar Lighthouses Show the Wa y

The instrument demonstration is the first step in realiz-ing pulsar-based navigation — a concept advanced aft e rthe discovery of these unusual celestial objects in 1967,Gendreau said. Pulsars are a subgroup of neutron stars.They rotate rapidly, emitting powerful beams of light

from their magnetic poles that sweep around as the starspins, much like a lighthouse. On Earth, these beams areseen as flashes of light, blinking on and off at interv a l sfrom seconds to sub-milliseconds.

Because of their predictable pulsations, “they are highlyreliable celestial clocks” and can provide high-precisiontiming just like the atomic clock signals supplied throughthe 26-satellite, military-operated Global Po s i t i o n i n gSystem (GPS), Arzoumanian said. Although GPS offershighly reliable location and time information to anyonewith a GPS receiver, it is geared to Earth-based applica-tions. As a result, GPS signals weaken the farther onetravels out into the Solar System. “Pulsars, on the otherhand, are accessible in virtually every conceivable flightregime, from low-Earth orbit to interplanetary to deepestspace,” Gendreau said.

To demonstrate the viability of pulsar-based navigation,Gendreau and his team, including the Massachusetts

Navigating by Cosmic BeaconsRevolutionary Navigation and Communication Payload Receives NASA Funding

About the Cover:

Photo Credit: Chris Gunn

Goddard astrophysicists Keith Gendreau and Zaven Arzoumanian have proposed a multi-purpose instrument to demonstrate a potentially game-changing navigation technologythat uses pulsars as a time and navigation standard. The instrument would realize theconcept of a pulsar-based map, whose pictorial elements are shown in the background.First used on a plaque attached to NASA’s Pioneer 10 spacecraft, the map’s radiating linesrepresent the positions and pulse periods of 14 pulsars, encoding the Sun’s location inthe Milky Way.

C o n t i n u e d , Page 3

Principal Investigators Keith Gendreau (seated) and Zaven Arzoumanian are fine-tuningtheir Modulated X-ray Source, which will play a pivotal role in the demonstration of thew o r l d ’s first X-ray communication system.

h t t p : / / g s f c t e c h n o l o g y. g s f c . n a s a . g o vVolume 7 Issue 3 Spring 2011

03Institute of Te c h n o l o g y, the Naval Research Laboratory,the National Institute of Standards and Te c h n o l o g y, andothers, will develop the XNAV experiment as a payloadon the International Space Station’s Express LogisticsC a rr i e r, an unpressurized payload platform. The instru-ment will use its 56 telescopes to detect X-ray photons inthese powerful beams of pulsated light to estimate theira rrival times. With these measurements, the system willstitch together an on-board navigational solution usingspecially developed algorithms.

If an interplanetary mission were equipped with such anavigational device, it would be able to calculate its loca-tion autonomously, independent of NASA’s Deep SpaceNetwork (DSN), Gendreau said. DSN, considered themost sensitive telecommunications system in the world,allows NASA to continuously observe and communicatewith interplanetary spacecraft. However, like GPS, thesystem is Earth-centric. Navigational solutions alsodegrade the farther one travels out into the Solar System.Fu rt h e rmore, missions must share time on the network,Gendreau said.

“ To better explore new worlds beyond low-Earth orbit,we will need additional navigational solutions. XNAVenables deep-space missions that are not feasible withE a rth-based tracking,” he added.

X-Ray Communication

The multi-purpose payload also will enable a demonstra-tion of the world’s first X-ray communication system. Thistest will feature Goddard’s Modulated X-ray Source(MXS), which turns on and off many times per second toencode digital bits for transmitting data. Since developingthe MXS with Goddard and Defense Department R&Dfunds, Gendreau has demonstrated 500 kilobyte-per- s e c-ond data rates using the device (Tech Trends, Summer2007, ). The goal is to one day transmit gigabytes ofdata per second with minimal power.

His plan is to fly the MXS on a supply spacecraft. As thec r a ft approaches the Space Station, MXS will transmit datavia the modulated X-rays, which the XNAV hardwarewould then receive.

Should the first space-based demonstration succeed,Gendreau said it would be laying the foundation for amore powerful way to transmit data across vast distances.“This is a baby step toward interplanetary X-ray communi-cation,” Gendreau said. “We understand these technolo-gies,” Arzoumanian added. “We understand how to buildthe payload. We need to show what is feasible. This exper-iment will tell us what we can do.”

C o n t a c t :[email protected] or 301.286.6188

[email protected] or 301.286.2547

Cosmic Beacons. . .Continued from page 2

Talk about getting more bang forthe buck. The same payload select-ed to help demonstrate two poten-tially “game-changing” technologieson the International Space Stationalso would allow astrophysicistsKeith Gendreau and ZavenArzoumanian, together with ane x p e rt science team, to study thenature of matter in neutron stars.

Responding to a NASA solicitationfor an Explorer-class mission, theteam has proposed the NeutronStar Interior Composition Explorer(NICER). The mission would sharethe same payload now being developed with NASA tech-nology funds (see related story, page 2).

“The hardware needed for the X-ray NavigationDemonstrator is identical to that needed for NICER, ”Gendreau said. “In fact, they share the same targets andoperational concept. The differences are on the back endin terms of how the data will be used.”

The principal scientific objective isl e a rning more about the interior com-position of neutron stars, the rem-nants of massive stars that, aft e rexhausting their nuclear fuel, explod-ed and collapsed into super- d e n s espheres about the size of New Yo r kC i t y. Just one teaspoonful of theirmaterial would weigh a billion tonson Earth. “NICER will uncover thenature and probe the physics of ultra-dense matter in these stars,”Gendreau added.

Although neutron stars emit radiationacross the spectrum, observing in the

X-ray band offers the greatest insights into the objects’t h e rmal, magnetic, and rotational characteristics. As aresult, the experiment package will carry 56 X-ray tele-scopes, silicon detectors, and other advanced technolo-gies.“NICER meets critical science objectives and is a step-ping stone for technology applications that meet a varietyof NASA needs,” Gendreau said. “It’s rare that you get ano p p o rtunity to do a crosscutting experiment like this.”

More Bang for the Buck

Clouds of charged particles move along thepulsar's magnetic field lines (blue) and create alighthouse-like beam of gamma rays (purple) inthis illustration.

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McGill said CATS will be a hybrid instrument combiningcapabilities available on a similarly named instrument thatMcGill developed specifically for NASA’s ER-2 aircraft .That instrument, affectionately known as “airplane CAT S , ”was tested for the first time in April. It also incorporatesthe capabilities of McGill’s Cloud Physics Lidar, which heand his team demonstrated on the inaugural flight ofN A S A’s unmanned Global Hawk aircraft last year (T e c hT r e n d s, Summer 2010, Page 5). Both were developedwith Goddard and Earth Science Technology OfficeR&D funding.

“This is the perfect success story,” McGill said. “Theseinvestments led to this award.”

A Goddard scientist, who has built and deliv-ered five different aircraft - b o rne instruments injust 12 years, has been selected to build yetanother — this time, a dual-frequency lidarthat will fly a little higher in altitude on theI n t e rnational Space Station’s JapaneseExperiment Module (JEM).

In March, NASA announced it had selected theC l o u d - A e r o s o l -Tr a n s p o rt System (CATS) as oneof the first U.S.-provided “hitchhike r- t y p e ”i n s t ruments to be installed on JEM’s ExposedFa c i l i t y, an attached payload carr i e r. The instru-ment, which will showcase data-gatheringtechniques important to future missions, willbe completed and delivered in two years.

“They looked at us and acknowledged we hadbuilt five instruments in a relatively short peri-od of time and that we had a track record fordeveloping high-altitude, small, autonomouslyoperated instruments on time and on budget,”said scientist Matt McGill, who is managing thei n s t rument’s development with his colleague,Stan Scott. “It’s a perfect payload for SpaceStation and it’s a good opportunity for us.”

From its Eart h - o b s e rving perch, CATS will pro-vide long-term observations of clouds andaerosols — tiny particles suspended in theatmosphere — to study their influence onatmospheric circulation and precipitation. Ofp a rticular interest to Earth scientists is the abil-ity to track in near real time aerosol plumessuch as those created in sandstorms or vol-canic eruptions. “The space station orbit isideal for tracking plumes and studying theirdaily effects,” McGill said.

It also will test an experimental channel that will directlymeasure microphysical properties of clouds and aerosols— a capability identified for the proposed Aerosol-Cloud-Ecosystems (ACE) mission recommended by theNational Research Council’s Decadal Survey for Eart hS c i e n c e .

Data Continuity

Just as important, CATS will ensure the continuity ofcloud and aerosol data. Curr e n t l y, CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite), a jointmission with the French space agency, CNES, is provid-ing that data. However, “the U.S. will have no aerosol orcloud profiling capability from space after CALIPSOends,” McGill said. ACE, should NASA decide to fund themission, isn’t expected to fly until 2020. “Our instru m e n twill help fill the data gap,” McGill said.

Volcanoes such as those shown here produce ash and prodigious amounts ofsulfur dioxide, which interact with air to produce sulfate aerosols. The Goddard -developed CATS instrument will monitor clouds and aerosols from its perc ho n b o a rd the International Space Station.

NASA Lets the ‘CATS’ Out of the BagNew Instrument to Observe Clouds and Aerosols from the International Space Station

C o n t a c t :M a t t h e [email protected] or 301.614.6281


05When 30 NASA engineers set out tobuild and test an experimental crewmodule made entirely of lightweightcomposite materials a few years ago,little did they know that their workultimately would benefit scientistsdeveloping a one-of-a-kind instru-ment designed to profile tropospher-ic winds — a key measurement forimproving weather prediction.

But that’s precisely what has hap-p e n e d .

A Goddard team, led by PrincipalInvestigator Cathy Marx and Earth sci-entist Bruce Gentry, has tapped thee x p e rtise of Goddard materials engi-neer Dan Polis to build what isbelieved to be the first complex, con-toured unibody structure built of alightweight carbon-fiber epoxy mate-rial. Unibody or monocoque con-s t ruction is a technique where anobject’s exterior supports its stru c t u r-al load rather than an internal frameor truss.

Polis was one of 30 NASA engineerswho participated in an 18-monthtiger team challenge to design, build,and test the 12-foot-wide CompositeCrew Module — an effort started forthe sole purpose of giving engineersin-house experience designing and constructing complexs p a c e c r a ft with composite materials (Tech Trends, Spring2007, Page 7). The team completed the crew module in2 0 0 9 .

In part i c u l a r, Polis is leveraging what he learned to helpadvance Goddard’s Tropospheric Wind Lidar Te c h n o l o g yExperiment (TWiLiTE), the first and only molecularDoppler lidar system to profile winds. Designed to oper-ate autonomously on high-altitude aircraft, the advancedi n s t rument is slated to fly on the NASA Global Hawk in2013 as part of NASA’s four-year Hurricane and SevereS t o rm Sentinel (HS3) mission aimed at discovering whyh u rricanes intensify (Tech Trends, Summer 2010, Page 4).

TWiLiTE Design

T WiLiTE gathers wind data by transmitting ultravioletpulses through the atmosphere. A small fraction of thelaser signal scatters off molecules in the atmosphere andr e t u rns to the instrument where it is collected by the tel-escope. An onboard Doppler receiver analyzes the

r e t u rn signals to determine wind direction and speed.Although the molecular system is not as precise as othermeasurement techniques, the advantage of such a systemis that molecules are omnipresent and signals can bemeasured anywhere, including in clear air.

Though unique, TWiLiTE is undergoing a metamorphosisto make it more capable and better suited as a space-based instrument for the 3-D Tropospheric Winds missionrecommended by the National Research Council’sDecadal Survey for Earth Science, Gentry said. “The tech-nology we’re putting into the system extends the instru-ment beyond the airborne system to space-based use,”he said.

S p e c i f i c a l l y, he, Marx, and Goddard engineers Pat Jordan,Ed Faust, and Pete Dogoda are using Goddard and NASAE a rth Science Technology Office R&D funds to add aninfrared channel to measure signals scattered off tiny par-ticles or aerosols in the atmosphere if any are present.

First-Ever Unibody Composite Telescope DevelopedTeam Leverages Knowledge from Composite Crew Module Challenge

C o n t i n u e d , Page 8

G o d d a rd engineers are leveraging lessons learned building the Composite Crew Modulep i c t u red here to create the first unibody design for a telescope. The structure will be usedfor an Earth science instrument.

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used film used as a thermal insulator on instru m e n t s .Components made of silver Teflon returned homeripped. Some coatings and materials even oxidized to thepoint where they had disappeared.

To understand what had caused the damage, NASA engi-neers carried out flight experiments on various SpaceShuttle missions and the International Space Station.They developed predictive models. “We learned from theShuttle experience. We learned what materials to use andwhat materials not to use on the outer surfaces of space-c r a ft and instruments operating in low-Earth orbit,”Carosso said. “We thought we had the problem licke d . ”

Based on her team’s analysis, however, that doesn’tappear to be the case.

To avoid future degradation of instrument components,Carosso and Hughes have proposed a multi-facetedresearch effort to find out just how the molecule slithersits way into instruments. They also plan to establish a lab-o r a t o ry where they would test different detector materi-als to determine which are immune to degradation.

The information is critical to instrument designers,Hughes added. Atomic oxygen, already plentiful in low-E a rth orbit, increases in relation to solar activity.U n f o rtunately for potentially vulnerable instruments, theSun is entering its solar maximum, the cyclical period ofgreatest solar activity.

“We never suspected that atomic oxygen could get insidea spacecraft,” Carosso explained. “We thought we under-stood the problem for high-energy atomic oxygen ru i n-ing external surfaces; now we see evidence of intern a ls u rfaces being degraded. So now, here we go again,”Carosso said. “We’re the ones building hardware. Weneed to thoroughly understand what’s going on here.”

Decades ago, NASA engineers figured out how to preventa highly pervasive molecule in low-Earth orbit fromdestroying materials commonly used on the external sur-faces of spacecraft and components. Imagine their sur-prise when scientists discovered signs of degradationdeep within the Hubble Space Te l e s c o p e .

“We thought we understood the problem,” said NancyCarosso, chief engineer of Goddard’s Contamination andCoatings Engineering Branch. She and her colleaguesnow have found evidence that the internal surfaces ofHubble’s Corrective Optics Space Telescope AxialReplacement (COSTAR) instrument had degraded duringits many years in space. COSTAR was returned homea fter astronauts replaced it in 2009 with the CosmicOrigins Spectrograph (COS).

The culprit? Based on ground tests and other sleuthing,the degradation likely was caused by low-velocity atomicoxygen molecules finding their way inside the instru m e n tand ricocheting off the surfaces, Carosso said.

Scientists discovered the COSTAR problem by accidentduring an investigation into why COS was showing signsof possible degradation. Although COS’s science capabili-ties are in no immediate danger, the sensitivity of thei n s t rument’s windowless cesium-iodide detectorsappears to be degrading five percent or more per year.

As part of the investigation, which is still continuing, engi-neers with the Contamination and Coatings EngineeringBranch asked the Smithsonian Institution — nowC O S TA R’s official guardian — for permission to obtain asample of COSTA R’s ribbon cable. Though engineerscouldn’t see any visible damage to the cable, a lookunder the microscope and chemical analysis told a differ-ent story. The sample was pitted — a telltale signature ofexposure to atomic oxygen.

Even if atomic oxygen isn’t causing COS’s degradation,the presence of atomic oxygen inside Hubble is a warn-ing to other instrument designers, said David Hughes, asenior engineer who examined COSTA R. Developers ofthe Air Force’s Special Sensor Ultraviolet Limb Imager, forexample, also have noticed degradation of their instru-ment’s cesium-iodide detector. “We might be the firstpeople to have thought that atomic oxygen is to blame,but we’re not the first to have experienced the mole-cule’s ill effects,” Hughes said.

This isn’t the first time engineers have waged war againstthe corrosive effects of atomic oxygen.

Engineers first became aware of its harmful effects in the1980s. Materials exposed to the molecule while the SpaceShuttle orbited the Earth at high velocities — part i c u l a r l ythose enshrouding payloads stashed in the opened cargobay — showed obvious signs of serious wear. The high-velocity impacts etched or “frosted” Kapton, a commonly

Attack of Atomic Oxygen: Molecule Slithers into the Spotlight

C o n t a c t :N a n c [email protected] or 301.614.7038D a v i d . [email protected] or 301.286.4986

Engineers Nancy Carosso and David Hughes are pictured herewith spacecraft components that had been damaged due toe x p o s u re to atomic oxygen.


07With the successful demonstration ofa football field-sized super- p r e s s u r eballoon in Antarctica earlier this year,engineers say they have passed amajor milestone in their quest to pro-vide scientists with a “satellite on astring” — a platform that will providelong-duration, low-cost access to nearspace. Work now begins on an evenlarger vehicle capable of flying one-ton scientific payloads.

In January, engineers successfullylaunched a 14-million-cubic-foots u p e r-pressure balloon from the RossIce Shelf in Antarctica. Tw e n t y- t w odays later, after making a full orbit at aconsistent altitude of 111,000 feet,the pumpkin-shaped balloon wasbrought down to ensure recoverabili-ty of its payload.

The flight validated changes engi-neers made to scale up from a 7-mil-lion-cubic-foot design tested in late2008 to its current size capable of carrying 4,000 poundsof suspended weight. It also laid the groundwork for theultimate balloon — a 26-million-cubic-foot version, whichwould be even larger in diameter than a football field andcapable of staying aloft for up to 100 days. The team plansto demonstrate it in 2013.

“We’re on the verge of supporting science for significantlylonger durations,” said David Pierce, chief of the NASABalloon Program managed by the Suborbital and SpecialOrbital Projects Directorate at the Wallops Flight Fa c i l i t y.“It’s exciting to see this engineering development becom-ing an operational reality. ”

Rivals Satellites

Wallops began developing these pressurized floatingbehemoths nearly a decade ago as a viable alternative toorbiting spacecraft and to extend the capabilities of theBalloon Program’s current offerings. Made of a co-extru d-ed polyethylene film no thicker than ordinary plasticfood wrap, super-pressure balloons are pressurized justenough to maintain their volume so that cooler night-time temperatures do not affect the float altitude. As aresult, they are able to maintain a consistent altitudeabove 99 percent of the atmosphere for weeks at a time,making them competitive with satellites for investigationsthat can be done in near space. An added advantage isthat scientists can retrieve, refurbish, improve, and reusetheir payloads during subsequent balloon missions.

Zero-pressure balloons, on the otherhand, are not pressurized andexpand and contract with changes intemperature. That means these bal-loons — NASA’s current workhorses— must vent gas during the daytimeand drop ballast, usually sand, atnight to maintain an operable plat-f o rm. Eventually, one or the otherruns out and the mission ends, usu-ally within a few days if flying at midl a t i t u d e s .

Engineers have long known theadvantages of pressurized balloons.The problem is they are difficult tobuild. “We’ve never done anything ascomplicated as these balloons,” saidChief Designer Rodger Fa r l e y. Inaddition to determining the mosteffective shape, the Wallops teamhad to make sure the polyethylenematerial could withstand the pres-sure and not degrade due to expo-sure to ultraviolet radiation. This

required intensive analysis and testing. “We’re trying todo something that hasn’t been done before,” added Te s tManager Henry Cathey.

The team intends to execute another test flight inDecember 2011, and ultimately declare the 14-million-cubic-foot balloon fully operational by 2013, said BalloonProgram Chief Technologist Debora Fa i r b r o t h e r.

Work Continues

Meanwhile, work continues on the largest version of thes u p e r-pressure balloon fleet, the 26-million-cubic-footcolossus that can carry one-ton scientific payloads toabove 100,000 feet, which is up to four times higher thanwhere planes fly. Fairbrother believes the team will beready for the first test flight of this balloon in 2012.

Their availability won’t come too soon for the scientificc o m m u n i t y, said John Mitchell, deputy project scientistfor the Balloon Program. When development is com-plete, scientists will have another platform from which toc a rry out their research from Earth and even in missionsto other planets. “That’s the big thing,” Mitchell said.“They give us another tool.”

“It’s encouraging to us,” Cathey said. “We have a productthat scientists are anxious to use.”

C o n t a c t :D a v i d . L . [email protected] or 757.824.1453

Up, Up, and Away with NASA’s Satellite on a String Wallops Team Demonstrates 14-Million-Cubic-Foot Pressure Balloon

In January, engineers successfully launched a14-million-cubic-foot super- p re s s u re balloonf rom the Ross Ice Shelf in Antarc t i c a .

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G o d d a rd Tech Tre n d sG o d d a rd Tech Tr e n d s is published quarterly by the Office of the ChiefTechnologist at the Goddard Space Flight Center in Greenbelt, Md.The newsletter describes technology developments at Goddard andexplains how they are helping NASA to achieve its missions. If youwant more information about Goddard technology, contact ChiefTechnologist Peter Hughes. If you wish to be placed on the newsletterdistribution list, contact the editor.

Peter M. HughesChief Te c h n o l o g i s t

3 0 1 . 2 8 6 . 2 3 4 2Pe t e r. M . H u g h e s @ n a s a . g o v

Lori J. Ke e s e yE d i t o r

3 0 1 . 2 5 8 . 0 1 9 2l j ke e s e y @ c o m c a s t . n e tNP-2007-10-853-GSFC (revised 5/11)

With both channels, TWiLiTE will be able to profilewinds under any atmospheric conditions.

The team also is reconfiguring the telescope optics toprovide multiple viewing angles needed for profilingthree-dimensional winds. Instead of installing just onetelescope, which is typical of most lidar systems, thenew-and-improved TWiLiTE will be equipped with fourtelescopes positioned 45 degrees apart off nadir on as t ructure that looks something like a space capsule.Both the ultraviolet and infrared laser beams will becombined into a common optical path and a small rotat-ing mirror will select one of the four telescopes fromwhich to transmit the beams. On their return, the sig-nals will be separated and sent to either the aerosol ormolecular receiver.

Building Unusual Telescope Housing

How then to build this unusual housing for a telescopesystem? The team originally planned to build the stru c-ture from machined aluminum parts, but decided to usecomposite materials because of their relative stiffnessand immunity to distortions caused by changes in tem-perature. “We knew what we wanted to do. Compositesoffered the perfect solution, but we didn’t have the toolsto develop the structure,” Jordan said. Starting fromscratch was not an option, either, particularly for a com-plex technology-development project with a limitedbudget and tight schedule.

Enter Dan Polis and the Goddard Composite MaterialsEngineering Technology team. “What we’re doing is tak-ing lessons learned in aircraft design to develop a three-foot-wide telescope,” Polis said.

Although Goddard has a rich tradition creating customcomposite components for a variety of scientific instru-ments, it has never built anything quite like this for a sci-ence application, Polis said. “This is the first unibodydesign for a telescope.”

The structure, which features four portals from whichthe telescopes will point, will be made of only twopieces of carbon-fiber epoxy formed over a foam moldand cured under relatively low pressures, Polis said.

C o n t a c t :B ru c e . M . G e n t [email protected] or [email protected] or 301.286.2434

C a t h y. M a [email protected] or 301.286.2073D a n i e l . L . [email protected] or 301.286.6731

Other than for the two composite shells that the teamwill bond together, the structure will have no parts thatmust be fitted together with clips, plates, or fittings. Norwill these parts be cured in an autoclave, a type of pres-surized oven, under high temperatures and pressure. Asa result of this “out-of-autoclave” process, the stru c t u r eis expected to cost a quarter of the price and take halfthe time to manufacture compared with more tradition-al fabrication techniques. The team expects to deliverthe structure this summer in plenty of time for Gentryto prepare the advanced instrument for its flight on theHS3 mission in 2013.

“It’s very satisfying to have the fruits of our labor — par-ticularly in designing complex, three-dimensional com-posite structures — transition so beautifully into futureventures like TWiLiTE,” said Jeff Stewart, who served asthe deputy project manager on the multi-centerComposite Crew Module tiger team. “This is a uniqueapplication of what we learned over that months-longe f f o rt.”

C o m p o s i t e. . . Continued from page 5

This is a drawing of the composite telescope structure beingdeveloped for Goddard ’s TWiLiTE instrument.

national aeronautics and space administration · 2013-02-02 · material would weigh a billion tons...

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